text:
C172N Skyhawk II fuel drain handle operation for people < 180cm
I'm asking for a friend - literally.
One of our club's planes is an old workhorse used a lot for training. She's got a fuel drain handle in the inspection hatch where one checks the oil.
I've never had a problem to place an inspection cup under the cowling and, although looking awkward, to then reach to the inspection hatch and pull the handle.
My friend is a lot shorter than me and doesn't reach.
Do you have any suggestion of how to go about it? Since I don't have that problem I'm not sure how to go about a solution.
The handbook suggests to let it drain for I believe 4 seconds - which is a lot of fuel, color additive and lead. Although it evaporates quickly it'd be a shame.

If they can't reach with a cup, they shouldn't be letting it run onto the ground. If on grass it burns out the grass, and if on asphalt it damages the asphalt (by dissolving the tar component).  Plus you can't inspect it.
An airport owner will give you an earful if you're seen running gasoline onto the pavement.  If you absolutely must, drain it on gravel or sand.
If I had that problem I'd just take a piece of shoelace cord or string and wrap it around the drain handle so I could pull it up with my hand outside the access hatch.
Or as a Plan B if I can't get a straight pull with a piece of cord, tape the inspection cup to a stick to hold it where it needs to be.  A little improvisation goes a long way.
If the fuel in the sample is clean, it should be dumped back into the fuel tank.  If it's not clean, on a patch of gravel or into a disposal container if the airport provides one.

I wouldn't say you can't inspect it if you dump it on asphalt or concrete, it actually can tell you a lot. Fuel evaporates very quickly, after a couple of minutes if there's anything left it's water in the line. Not that I advocate that method.

You'll see water yes but not particles of crap that could be accumulating on the outlet screen.

Thanks for the suggestion. I was building a handle for the cup but its easier to build a clipable connection to the handle. Used some paper to form and some glas and epoxy to build it, works great.

Four seconds is a long time, but if the fuel is still good you can put it back in the tank. It's a bit of an annoyance, yes, but the reason is to make absolutely sure the fuel line is clean. Unless you have a long run-up and taxi the fuel in the line will be hitting your carburetor on your climb-out, which is the worst possible time for your engine to fail due to water ingestion.
Draining the fuel is tricky if you can't reach both the drain and the valve as the valve doesn't spring back on its own. I think it's meant to, but over time loses that capacity and you have to push it back firmly or fuel keeps coming out of the drain. A clever solution I've seen once was putting the cup on the end of a stick. If it was me I'd rig this using bent wire coat hanger, but duct tape would probably work fine too.

Thanks, I'll have a go bending a wire hanger. Good idea


text:
EASA - Legal Alternate when ILS to a specific RW is U/S
Interesting question this morning. My alternate has RW07/25; the ILS to 25 was U/S. TAF was for OVC007.
My alternate minima are:
If DH < 250 then use DH + 200. With the ILS inop, had I needed to land on 25 I would have been down to LNAV with a higher DH - if DH >=250, I need to add 400 ft. With that approach, my ceiling requirement was slightly above 700 ft.
There were predominantly easterly Winds today, but what if it is a crosswind or changeable - may I "assume" what the active runway may be and choose the "likely" one? This is about legality, not so much practicability or even safety aspects, but there aren't many viable alternates around my home airport.
I can't really find an interpretation for a case such as this.

EASA Part-CAT does not distinctly discuss unserviceable (U/S) runways when it comes to destination alternate requirements. (AMC2 CAT.OP.MPA.182 (Destination Alternates), AMC5 CAT.OP.MPA.182 (Safety Margins for Met Conditions), AMC6 CAT.OP.MPA.182 (Planning Minima)
However, AMC3 CAT.OP.MPA.182, gives information concerning the application of TAFs to pre flight planning -  discussing wind speeds to be within required limits. Therefore, the planning minima requirements must concern the selection of a runway at your potential destination alternate. In other words, the TAF will determine which is the legal, active runway (for your flight plan, ETA +/- 1 hour).
For your example, if the TAF forecast easterly winds, then RWY07 can legally be assessed as the active runway in terms of planning minima AMC6 CAT.OP.MPA.182 (Planning Minima). (Or, RWY25 could be assessed if within your tailwind allowance - type/operator specific - though you probably wouldn't in this instance due to the ILS U/S).
If the planned active runway is within the safety margins for met conditions (AMC5 CAT.OP.MPA.182) and the planning minima can be met, only this one destination alternate will be required to be listed on the operational and ATS flight plan. (AMC2 CAT.OP.MPA.182(a)) Otherwise two destination alternates will be required legally to be listed on the operational and ATS flight plan (AMC2 CAT.OP.MPA.182(b)).
(What the airport operator actually determines as the actual runway in use  is different from the met conditions and planning minima determination of one/two destination alternates for the IFR flight plan before you fly.)

(This answer presumes IFR flight and concerning aeroplanes, not helicopters)

Thank you for that detailed answer, very helpful. I've been trying to find an equivalent in NCO, but it looks different there. NCO.OP.160 only talks about the aerodrome itself. GM2 NCO.OP.160 merely recommends to take into account e.g. surface conditions and winds.
@tedioustortoise could I ask your opinion of the same question under Part NCO?

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


text:
Artificial horizon - "horizon bar" or "symbolic airplane adjust"
(Student pilot, ~ 22hrs training)
On a box-standard AI in a C172 there is a knob that allows you to move the symbolic airplane up and down. I've never managed to ask what it is for, but have now been intrigued enough to google it. An RC Allen instrument manual points out that it "adjusts the Symbolic Airplane to compensate for viewing parallax. Adjust Symbolic Airplane so that it is visually aligned with the horizon from pilot’s normal sitting position."

Two questions:

My best guess is that I could/should adjust it during the run-up along with the "instruments check" item on the checklist. However, is the Cessna always sitting correctly for that to be exact (or exact enough)? If there is a slightly different pressure in the nose wheel oleo the nose wouldn't necessarily point to the horizon, or when there is a slight slope of the taxiway/run-up area. Would it be better to (re-)adjust it in level flight?

Why do more modern AIs no longer appear to need that? The viewing parallax is still there, why isn't the button?

Instrument parallax has to do with viewing position of the pilot compared to the instrument. You adjust the symbolic airplane to the horizon bar on the outside of the instrument, not the part that moves, so you don't have to wait for it to spin up or find flat ground. I do it as part of my pre-start instrument checks, after adjusting my seat.
All mechanical AIs should have an adjustment mechanism, but many modern ones are digital, with a flat screen. You can't have parallax error with a screen because there is no distance between the needles and the reference measurements.

So pre-start, after adjusting your seat, you just put the symbol on the horizon line and you're done?

Exactly @ExternalUse. I'll edit to point out it is post seat adjustment.

@ExternalUse - Actually, I’ve always adjusted the Symbolic Airplane after I start the actual airplane engine, usually during runup. The AI needs at least five minutes to spin up its gyroscope and stabilize before I cage it in the level-with-the-horizon position.

@DeanF. , you are supposed to adjust it to the horizon bar on the outside of the instrument, not the attitude card.

You may need to adjust it in cruise flight.  If the attitude on the ground differs from that needed to hold altitude at your chosen airspeed.

@GdD Thanks, that is important info to align it with the two bars on the outside of the instrument. I'll remember that.

Adjusting the aircraft symbol while on the ground may be a starting point, but the Pilot's Handbook of Aeronautical Knowledge (FAA, 2016) states "Normally, the miniature aircraft is adjusted so that the wings overlap the horizon bar when the aircraft is in straight-and level cruising flight."
So, once in level cruising flight, adjust the airplane symbol to the indicated horizon. NOTE: On digital displays you can't adjust the aircraft symbol and you may see an indication of a slight positive or negative pitch angle while in level cruising flight. The Cirrus SF50 shows a negative pitch angle during cruise.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Are runways booked by airlines to land their planes?
Suppose Indigo lands at Indira Gandhi international airport and the arrival is schedule at 5:30 a.m. Is the runway to land on fixed by the airline.
If not please explain reason behind not to schedule the runway on which the flights will land.

No one can "book" runways. Traffic on a runway is managed by air traffic control, whose job it is to ensure a safe and expeditious flow of air traffic. Generally speaking, a place on the runway is assigned on a first-come first-served basis.
You may want to explore the air traffic control tag to learn more.

You can't book the runway, but often you reserve the capacity of the airport by booking a slot.

@DeltaLima Agreed, a complete answer to the question should explain the relationship between a landing slot (which is assigned/reserved) and the actual time the plane lands on the runway.

A VVIP, say a head of state, can book a runway. Though this mau happen at some secondary airport, not the primary one.

@vasin1987 In the case of a VVIP, they may close the entire airport to other traffic, in which case the VVIP will likely to get whichever runway they request.

Yeah, in the case of the POTUS, they will do exactly what @StephenS said. They halt all other movement on the field while Air Force 1 is moving. They also put a TFR around the whole area.

What does it mean to "come"? Get into the ATC area?

In the USA at the large international busy airports, the airlines have to reserve a landing time slot for arrivals.  Indira Gandhi international airport might do the same. "A landing slot, takeoff slot, or airport slot is a permission granted by the owner of an airport designated as Level 3 (Coordinated Airport), which allows the grantee to schedule a landing or departure at that airport during a specific time period."
The choice of runway is determined generally by the wind direction. However,
"Delhi Airport has three near-parallel runways:

runway 11/29, 4,430 m × 60 m (14,530 ft × 200 ft) with CAT IIIB instrument landing system (ILS) on both sides
runway 10/28, 3,810 m × 46 m (12,500 ft × 151 ft)
runway 09/27, 2,813 m × 45 m (9,229 ft × 148 ft)."

So choice of runway might be driven more by how low the clouds (ceiling) are and the equipment on the airplane.

I just found a news story from 2014 about some airlines losing their landing slots at Delhi due to refusing to operate with Cat III compliant aircraft and trained pilots. So I'm pretty sure they have landing slots there.

Thanks for the backup. :)

Even with 3 parallel strips of pavement, there are still six runways, and the ones available will vary depending on wind and other factors.

@MichaelHampton Yes, but "landing slots" doesn't equal "reserved exact time on the runway." It just means you have permission to use the runways, a gate, etc. at around that time. These are separate from ATC slots, which are assigned on a first-come, first-served basis (and may not be used at all at times where they aren't needed.) Planes don't actually line up to land (or take off) in the order of their landing slot times.

@reirab: and presumably doing a go-around doesn't require you to pay for another slot after "wasting" the first one, because a financial disincentive to make the safe choice is always a bad thing.  From that it's obvious that actual ATC landing slots have to be different from traffic-capacity bookings.  (Unless my reasoning is totally wrong; I'm not an aviation expert at all.)

I would also imagine that "reserving a landing slot" is more to assist organizing the gigantic task that is traffic management. If 20 aircraft all try to reserve the same time frame, I'm pretty sure that the last several people will be told they might want to expedite or delay their departure because their landing time probably won't be what they expect.

Incidentally, only 3 airports in the U.S. are slot-controlled and only one of those is a large international airport (JFK.) DCA and LGA are the other two and both are mostly just domestic flight with a few short international flights (e.g. to Canada) mixed in. At least in the U.S., slot controls are only used for airports that are operating at or near the capacity of their runways. Most large international airports in the U.S. are built in places where they can build more runways when they need them. The two busiest have 5 parallel runways each that can all be used simultaneously.

"Most large international airports in the U.S. are built in places where they can build more runways when they need them."  I'd have to seriously disagree with that. Looking at the top ten busiest airports https://en.wikipedia.org/wiki/List_of_the_busiest_airports_in_the_United_States and then looking at each one at maps.google.com, only Denver International has room to expand - every place is either landlocked by surrounding highways and development, or by water.

The reason why airports don't schedule exact times and runways for take-off and landings are that there are far too many factors that are unpredictable in advance to know exactly when a plane is going to take off or land or which runway(s) will be available at that time.
If a plane arrives at an airport earlier than scheduled, it makes no sense to have them fly holding patterns wasting fuel instead of just going ahead and sequencing them to land. On the flip side, if a plane arrives later than scheduled, they still have to land. You can't just tell them, "Sorry, you missed your scheduled time, you have to divert or crash now." Similarly, if there are a bunch of planes waiting to use a particular runway (or if a particular runway is unavailable,) there's no reason not to just use another runway, provided there's another one available that meets the wind and performance needs of a given aircraft.
Flight times for airliners are typically scheduled many months in advance. Yet, many factors that can affect their departure, arrival, and total flight times aren't knowable more than a few hours in advance, if that.
Some of the factors that can affect times include:

Weather shuts down the departure airport during the normal departure time.
The aircraft is out-of-position due to an earlier delayed flight.
Part or all of the flight crew and/or cabin crew is out-of-position due to an earlier delayed flight.
The aircraft has a maintenance issue that causes a delayed departure.
The planned aircraft has a maintenance issue that prevents it from departing entirely and another aircraft has to be brought in to operate the flight.
Another aircraft had an emergency and required priority handling.
Wind. Winds aloft vary by the day and even by the hour. Schedules planned months in advance can only guess how long the actual flight is going to take based on seasonal averages. Actual weather is very often quite different from seasonal averages. Strong tail winds can allow a flight to be completed much faster than expected, while strong head winds can cause a flight to take much longer than expected or, in extreme cases, even cause it to have to divert to add fuel before continuing on to the destination.
Weather shuts down the arrival airport, causing the flight to circle until the weather clears, divert to another airport, or, if known far enough in advance, hold at its departure airport until the weather clears at the destination.
Weather en route shuts down the possible routes for the flight for a while, forcing it to wait, even if the weather at the origin and destination airports is clear.
Passengers board slowly, preventing the aircraft from pushing back on time.
Cargo isn't loaded quickly enough, preventing the aircraft from pushing back on time.
The flight is delayed by an ATC, pilot, transit worker, etc. strike (especially if the flight is in or near France.)
Passengers are connecting to the flight from another flight which arrived late and the airline decides to hold the plane long enough for the connecting passengers to make the connection.
The power fails at the arrival or departure airport.
The airline suffers a major IT system failure.
A passenger (or crew member) has a sudden health emergency.
The military attempted a coup in the arrival country, the departure country, or a country the flight needed to fly over.
The surrounding countries decide to close their airspace to the airline's country.
Someone set an Air Route Traffic Control Center on fire along the plane's route.

This is far from being an exhaustive list, but it should give a feel for why it's completely infeasible to schedule exact times for aircraft to takeoff or land on a given runway.
Similarly, there are several reasons why reserving a particular runway in advance is often not feasible:

Wind. At the vast majority of airports, different runways will be active depending on current wind direction and magnitude. As much as possible, you want airplanes to be both taking off and landing into the wind in order to allow for slower ground speeds during takeoff and landing (and, thus, less runway distance needed.)
Several larger aircraft may be arriving or departing that need a longer runway, so other traffic may be moved to a shorter one.
An emergency aircraft may require one of the runways to be closed to other traffic for a while.
A runway may be closed for maintenance (e.g. repainting stripes, removing rubber build-up, resurfacing, expansion, etc.)
A runway may be closed due to maintenance of other equipment in the runway environment (e.g. the lights, ILS, etc.)
A runway may be closed due to snow and/or ice (or the removal thereof.)
A runway may be closed for routine inspection.
A runway may be closed because someone decided to schedule a 5 km run on it.

This list is also far from being exhaustive.
Instead, airlines are assigned a specific block of time to use a gate along with a slot to land and takeoff. This allows the airport to plan the number of arrivals and departures that are likely to occur within a given hour to be less than the maximum capacity the runways are usually capable of handling, while not actually assigning a specific order for those arrivals and departures until they're actually ready for takeoff or sequencing to land. Then ATC can assign the most efficient runway currently available to each aircraft as they actually queue up for arrival or departure.
Even this is far from fool-proof, though. It's much better at handling real-world scenarios than scheduling exact departure and arrival times for each airplane would be, but events that affect a significant portion of the flights at the airport can still quickly lead to delays, especially during busy times of the day. Examples of such events would be storms near the airport, high winds at the airport, snow/ice at the airport, low visibility at the airport requiring more than normal separation between aircraft, a security incident at the airport, or the airport being LaGuardia.

What is it with French people and strikes?!

@Sean It seems that strikes are France's national pastime.

If anyone were to have a national pastime of air strikes, it logically ought to be Austria. ("Österreich").

"or the airport being LaGuardia" literally LOL! thanks - it's been a rough week and I needed the laugh!

"Sorry, you missed your scheduled time, you have to crash now."


text:
Wake turbulence: crossing under a final approach path VFR
Flying VFR around the Bay Area I’ve had two experiences recently that made me a bit nervous, but I haven’t been able to find recommendations that fit the situation.
The first was flying (C172) north along the east bay hills somewhere between OAK and LVK, around 3500’. We saw a 737 descending towards OAK ahead and above us, crossing right to left. 2 or 3 minutes later, long after I’d forgotten about it, I think we crossed the descending wake: we felt a single very sharp bump, hard enough to feel like we’d hit something.
The second time, I was crossing the bay just east of SQL on a northeast heading. ATC pointed out an A380 on final to SFO ahead of us. They passed in front and above us, and I turned to cross their path at 90 degrees, thinking this would be the right strategy for minimizing the risk of being rolled by the vortices. When I later checked the flightradar data, they were about 1000’ above us where our paths crossed. We never felt a bump, though the controller who watched this asked me how the turbulence was, so he evidently thought we were taking a risk.
Of course I know the mantra about wake turbulence is to just avoid it. But in practice, in a situation like this, I might have to divert for 5 minutes or so to try to fly “around” the wake area (e.g., in this case turn SE paralleling the flight path in reverse before turning back on course) and it seemed to me that crossing a wake at 90 degrees seems like a reasonably safe thing to do, a couple of minutes after the plane had crossed (though I couldn’t really judge the vertical separation).
I can’t find anything in faa docs on this situation. They’re all about takeoff and landing. And the bad stories about planes being damaged/destroyed by wakes seem to always involve a near 0 or 180 relative heading (i.e., flying along the vortex line so the two wings see a large force difference).
I’m curious what others think about this.

I passed through the remnants from from a Fedex DC-10 that had landed and was taxing to the ramp at an uncontrolled airport.I was about 2 miles south of the airplane approach path at about 1500 feet, more or less converging on it, and was going to join a downwind to go around and land in the opposite direction (wind was light and variable) to make sure I avoided his wake.  Except I must've hit his wake because I was hit with a single hard jolt in the glassy smooth morning air. I was downwind of the DC-10's approach path but thought I was well above it at that point, so it was quite a surprise.

Due to the nature of wake turbulence descending over time and weakening as time goes on, I would say that it's possible that you hit the wake of the 737, and just managed to avoid the A380's wake out of luck. It also depends on the wind direction as to the path of the wake, so it's hard to say in your specific case
Skybrary describes crossing wake turbulence as:

A cross-track encounter en route is likely to lead to only one or two sharp 'jolts' as the vortices are crossed.

Which leads to me to believe you hit their wake, and not just some other form of turbulence.
In terms of wake avoidance the FAA says in 7.3.7(b).9:

En route VFR (thousand-foot altitude plus 500 feet). Avoid flight below and behind a large aircraft's path. If a larger aircraft is observed above on the same track (meeting or overtaking) adjust your position laterally, preferably upwind.

And skybrary recommends:

In the case of crossing tracks, it has been found that the time interval necessary to avoid creating a wake vortex hazard is 3 minutes.

In terms of a direction to cross the vortexes at this section of FAA 7.3.3(b).1 implies that you should do as you did and cross perpendicular to the path - as to avoid strong induced rolls:

During inflight testing, aircraft intentionally flew directly up trailing vortex cores of larger aircraft. These tests demonstrated that the ability of aircraft to counteract the roll imposed by wake vortex depends primarily on the wingspan and counter-control responsiveness of the encountering aircraft. These tests also demonstrated the difficulty of an aircraft to remain within a wake vortex. The natural tendency is for the circulation to eject aircraft from the vortex.

To summarise those points in terms of enroute wake avoidance, and effect limitation:

Fly above their path
Position yourself upwind away from the wake path
Try to be at least 3 minutes behind the aircraft when crossing the path
And cross perpendicular to the wake path, to avoid inducing a roll

Sources: https://www.faa.gov/air_traffic/publications/atpubs/aim_html/chap7_section_3.html
https://www.skybrary.aero/index.php/En-route_Wake_Vortex_Hazard

Is a short, possibly violent pitch upset (crossing wake vortex) always preferable to a roll upset, regardless of vortex/encounter strength? Is it possible to exceed design load factor when crossing into wake vortex?

Taking a C172 for consideration,the design load factors(as given by: https://takewingaviation.com/wp-content/uploads/2017/02/N739EF_172N_POH.pdf)range from from +5.7g to -0.9g of the gross weight, and the effect of severe turbulence can be around 0.6g(http://capt-tom.blogspot.com/2016/05/g-force-in-severe-turbulence.html).These results would not indicate that severe turbulence could exceed the design load factor, hence crossing a wake would normally be described as less than severe turbulence,thus I wouldn't query the structure,and I would prefer crossing as oppose to possible loss of control.


text:
Vector to final on RNAV approach with the Intermediate and final segments are not aligned
Consider the RNAV 30 approach to C83 (Byron, CA),

On a recent training flight requesting vectors for the approach, ATC pointed us to the MOVDD IF before cutting us loose (informing us that we would be getting a vector to that fix). The segment between here and the FAF is 11 degrees off from the final segment. On a GTN650 at least (and I assume other similar Garmin devices), selecting “Vectors” as the approach method gives you the FAF line with your deviation from it & sequences from the FAF. This seems not correct for flying this particular approach. The best my CFI & I could come up with was to enter the approach as being flown from the IAF (SMONE) then select “Direct to MOVDD” sometime before reaching it (such as when ATC gives the last turn), after which the GPS will sequence to the intermediate-to-final segment. But this seems non-standard. What do others do in this situation?

I'm not a pilot, but it seems to me "Vectors" would be the wrong approach method if you're getting vectors to an IF rather than vectors to final approach course. When vectoring to an IF we can allow up to a 90º intercept, and you follow the approach course inbound on your own; when vectoring to final approach course there is a maximum 30º intercept.

@randomhead, I’m guessing you’re ATC? Why do you say vectors are the “wrong” approach method? In this case it was equivalent to “cleared direct to MOVDD” from a point where the intercept angle was ~90 degrees, so maybe not meaningfully different. But anyway, the question was more about “buttonology” with the approach.

I can't speak to the buttonology but it seems my intuition was correct according to wbeard52's answer. The "Vectors" method would be used when you're getting guidance to final approach course which is different from being pointed at a fix and told to proceed on the approach course from the fix. I don't know the nitty-gritty details of the difference; perhaps something to do with when the sensitivity of the simulated LOC needle changes? Though it does sound like you would have the same issue if you actually were to receive vectors to the 311º final between MOVDD and BABPI.

Learn the difference between Activate Approach and Activate Vectors to Final. HERE and HERE are two resources to get you started.

Not knowing the G650 (but I do know the G550, G1000 and G3000) what you would likely do is 1) From the Flightplan Page, select Direct to: MOVDD; 2) When appropriate (when cleared for the approach) select PROC a) ACTIVATE APPROACH (that is a single button on the G1000 and G3000...)

Selecting Activate Vectors to Final does something different. It draws a line from the TZ straight through the FAF and beyond. The unit 1) deletes all waypoints up to the FAF and 2) sets the shortest intercept of 90º or less. THERE IS NO TERRAIN CLEARANCE PROVIDED so that intercept might be through a mountain.

@dawg, I think it would be worth to write that as an answer.

What exactly were you cleared or instructed to do? "N12345, cleared direct MOVDD, cross MOVDD at or above 3000, cleared RNAV 30 approach", or "N12345, fly direct MOVDD, maintain at or above 3000, expect vectors to final", or something else?

@dawg - those are good links, especially the first one.

@Pondlife - The first. It appears that what my CFI and I did was the right thing, at least judging from some other tutorials I’ve found on line (following @dawg’s first link).

Since most fatal accidents are during approach, it is important to maintain 100% compliance with the procedure and have a clear understanding of what your FMS will do with different modes.
There is an important Garmin / FMS distinction between:

Selecting "Activate Approach" mode when navigating to a fix leading to an approach sequence, and;

Navigating directly to the FAF via ATC vectors by selecting  "Vectors to Final" ("VTF") mode.

If you select Vectors to Final in G1000 or G3000 (likely similar to your G650), the following things happen (from memory, I may have missed a few):

The waypoints in the flight plan are bypassed (but remain inactive in the plan and available to re-navigate direct to) and the FAF is made active;

Approach mode is engaged (which increases needle sensitivity);

If you have a non-GPS approach loaded, the frequency for that approach is made active and the needles switch to the relevant indication (green needles for ILS for example);

If you are navigating to a GPS waypoint, the FMS turns off lateral guidance and engages roll-mode (if you are in Heading mode, that mode is maintained);

The HSI Bearing Needle is set to the final approach course (or outbound course for a back course approach);

A graphical magenta line representing an extension of the line between the touchdown zone and the FAF is drawn on the map.

It would be unusual to use VTF (in IFR conditions) without being under some form of ATC guidance on vectors and terrain clearance - Hence 'Vectors' to Final. The use for VTF mode is usually when the pilot receives a clearance as follows:

ATC: N188L, six miles from BABPI, turn right heading 280, maintain two thousand six hundred until established on final approach course, cleared RNAV runway 30 approach Byron Airport.
Pilot: Right turn 280, two thousand six hundred until established, cleared RNAV 30 approach, 88L.

(The italicized sections are meaningful; look them up in the Pilot Controller Glossary)
At that point (assuming already at 2600), the pilot

Affirms the correct approach is loaded in the FMS flight plan;
Dials in 280º on the heading bug;
Engages heading mode, and;
selects Vectors to Final and the Garmin will then auto engage the approach from the FAF inbound. (Since this is a LPV approach, the Garmin will also intercept the vertical flight path.)

A contrary but common clearance might also be:

ATC: N188L, cleared direct MOVDD, cross MOVDD at or above three thousand, cleared RNAV runway 30 approach Byron Airport.
Pilot: Direct MOVDD, MOVDD at or above three thousand, cleared RNAV 30 approach, 88L.

In this case, there is a distinctly different FMS sequence:

Affirm the correct approach is loaded in the FMS flight plan;
Select MOVDD in the flight plan (this will be either an IAF or an IF);
Select Direct To - Enter - Enter to make active;
Select FMS mode (if not already selected and skipping the part to make sure the ship does not jump uncomfortably towards MOVDD);
Engage Approach Mode;
The Garmin will now auto sequence the approach including auto selecting green needles to fly an ILS or VOR if required. The Garmin will also intercept the vertical flight path if available.

You state in your question ATC pointed us to the MOVDD IF before cutting us loose (informing us that we would be getting a vector to that fix)
So what you do is:

Enter Direct To MOVDD and fly that course;
Select Activate Approach when you are cleared to fly that approach;
If ATC gives you a vector (perhaps because ATC does not want you to go straight there) then you enter heading mode and use the bug for that vector. Reset Direct To when ATC stops vectoring you.
Even if you receive a vector, you continue to have MOVDD as the active waypoint and you do not engage VTF unless you receive a clearance and a vector related to that clearance with the intent of you ending up on the final approach course near the FAF or a linear extension of the final approach course.

For illustration, consider the approach to KEGE (below, with the Vectors To Final magenta line drawn.
If you were to select VTF well outside of the IAF for this approach (and you were not under ATC POSITIVE CONTROL) there is a high risk that you would hit the 11,200 foot mountain just 7 miles from the FAF on the magenta line.
If VTF is engaged at a time when the pilot does not understand the sequence or limitations, BAD THINGS CAN HAPPEN! The FMS itself does not maintain terrain clearance for you.

Thanks for making clear the distinction between "vectors to final approach course" and "vectors to IAF/IF." OP's question, though, is what to do when the intermediate approach course they're being vectored to is not aligned with the actual final approach course to the runway. wbeard suggests dialing in a radial off a relevant fix (e.g. the 131º radial off BABPI or the 311º radial off MOVDD) and following that inbound to BABPI before actually selecting the "approach" to follow. Could you discuss that possibility in your answer?

Your current answer has the same problem as OP's question: If OP does actually receive vectors to the final (or rather, intermediate) approach course outside BABPI or MOVDD, they will be vectored to join a 314º/317º/311º course—but selecting "vector to final" will generate a 300º course to join instead.

@randomhead: If the expected vectors are not received to MOVVDD as expected, the pilot should clarify expectations with ATC. If the expected vectors are not received under actual IFR conditions, treat either rationally or as lost comm. It sounded actually as if this was a practice approach under VFR conditions and the controller became too busy to handle as expected (if I had to guess...)

@randomhead: Thanks for the edits btw. Useful!

I've read the answer carefully and I still don't see what OP should do if they receive vectors to intermediate approach course, i.e. the 311º or 317º course that is not in line with the 300º final approach course. This is not what happened, but hypothetically it could happen. If they engage VTF, will the GPS not draw a magenta line straight out at 300º, much as you show in your example at EGE? It would not be correct to follow that 300º course before reaching BABPI, so how should OP engage the system to intercept the correct intermediate course from the 280º ATC-assigned vector?

Is this an actual IFR approach or a VFR practice approach? It sounds like the later so ATC will not necessary vector in the same way for expediency. That is probably 90% of the problem here.  If this is an actual approach, ATC will either expect 1) the procedure to be flown as published (use the flight plan to do so) or 2) will issue vectors to an IAF (use the flight plan to navigate to that point) or 3) provide vectors to the final approach course with appropriate spacing outside the FAF. Only for number 3 would you use VTF.  Clear?

I am asking specifically about the third possibility: ATC provides vectors to the final approach course. But they will provide vectors to intercept the course at least three miles outside of BABPI, so the course to be intercepted is not the "final" approach course but an intermediate one. ATC will vector to a 30º intercept of the 311º course, and OP will intercept that course and fly to BABPI, turning left at BABPI to the 300º true final course. How will OP determine when they are established on the 311º course to BABPI? If they select VTF it sounds like they will only see the 300º course.

The segment from MOVDD to BABPI is not the final approach course; the extended line bearing 300º passing through BABPI and continuing on that same bearing is the final approach course. ATC could give a vector to intercept the final approach course (but they would need to specify that) and the intercept would be east of MOVDD. You would not be flying the 311º segment from MOVDD to BABPI and you would use VTF mode in this case. Or they could (more likely) specify a vector to MOVDD. You would use flight plan intercept in this case.

Hm. I don't have any non-aligned courses like that in my airspace but I fail to see any reason why ATC would not vector to the 311º course between MOVDD and BABPI. It's the thick black line depicted approach course segment outside the FAF. P/CG Final Approach Course—A bearing/radial/track of an instrument approach leading to a runway or an extended runway centerline all without regard to distance.

But 311º segment does not fit that definition - a constant 311º would put you EAST of the runway. It is by any definition an INTERMEDIATE APPROACH SEGMENT I do not believe ATC would vector an intercept between MOVDD and BABPI for many reasons such as the turning area not being defined for that segment and most FMSs not engaging vertical path guidance outside the final approach course. It is certainly possible to use an FMS to intercept that segment but the spoken clearance would take more time than just  clearing direct to MOVDD.

Let us continue this discussion in chat.

@dawg - This was an IFR approach, though conditions were VMC. There was significant weather in the area though, and the approach was pretty bumpy which made it extra exciting.

@FosterBoondoggle: If in actual conditions, and the clearance is unclear, ask ATC for clarification. You would program the FMS differently if you were expecting to engage the approach on an extend final, at an IF, or if the really want you to intercept a segment.

You stated ATC indicated they will give you vectors to the IF and not vectors to final (VTF).  Why would you select VTF when that is not what ATC is doing?  It's a rhetorical question but hopefully designed to allow you to realize that VTF is, in my opinion, the non-standard method.
I have flown lots of different GPS/FMS installations.  They all have VTF feature.  Some called it activate approach while other call it VTF.  All of these will provide guidance to the final approach capture fix (FACF) which is typically the waypoint in front of the FAF.  Some approaches don't have an intermediate fix outside the FAF and those may have a computer navigational fix (CNF) that the GPS / FMS uses to align the final approach course.  All CNF waypoints are surrounded by square brackets [CFBTF] as depicted on KICT ILS 01L.  You will only see the CNF waypoint if you do not select a transition on the GPS / FMS.
Others approaches, like the one you mentioned have multiple waypoints outside the FAF.  In this case, you will not see any waypoints outside the FACF (in this case, MOVDD).  If you were vectored to one of those you will need to select SMONE as the transition and let the FMS / GPS auto-sequence after you pass it.

Seems like my slightly educated guess was correct (OP selected "vectors to final" when they did not, in fact, receive vectors to final). But supposing they had actually received vectors to the 311º or 317º final approach segments, what would be the proper way of programming the GPS?

On a garmin,  I would would go direct to a waypoint that is along the 311 or 317 track.  I would then hit the OBS button and select the 311 or 317 radial.  You will see the magenta line on the screen move to align with the CDI.  You can then visually see the intercept ATC is giving you.  At some point (I don't remember when) you will need to deselect OBS for the approach to sequence correctly.

If ATC provided the unlikely instruction of “Fly heading xyz; vector to the intermediate segment between MOVDD and BABPI,” I guess I’d highlight BABPI in the flight plan, hit menu, and select “activate leg.” But I highly doubt that was the instruction.

@eater, why would you doubt there could be an instruction to intercept the approach course outside of the FAF? It seems in OP's case there was not, they were vectored to the IF instead. But vectoring to join a course outside the FAF is not uncommon by any stretch of the imagination.


text:
EASA Part-NCO; Approach light system
EASA Part-NCO, specifically OP.110, refers to 4 different lighting systems (NALS, BALS, IALS, FALS) to be considered when determining the landing minima. However, there are quite a few different systems, which in turn may vary in length, out there - nicely summarised in this article
Without using commercial vendors such as Jeppesen, how do you determine the lighting system "category" from the different plates?
Some examples, with the associated questions ahead of time:

for EKSP below, a 900m Calvert, is that really a Calvert-2 and would be in the FALS category?
And because 28L only has edge lighting, it would be NALS?
For EDDH, is ALSAF always FALS? Especially since the "LEN" mentioned in the table's header isn't actually given in the table below it?

In short, how do I "map" the actual light system to the "category" of approach lighting systems?
Denmark, Skrydstrup EKSP:

Germany, Hamburg EDDH


text:
Is the takeoff power always maximum?
I used to think that for commercial aircraft from Airbus, Boeing, Embraer, etc., the take off power was always maximum and selected by the TOGA selection on the thrust levers. But I have been told that some companies would lower the takeoff power to save money (at the expense of a longer take-off length).
So the question is: for regional, continental, and long-haul aircraft, is the takeoff power always maximum or can it be adjusted depending on the configuration? And can lowering takeoff power allow savings?

https://en.wikipedia.org/wiki/Flex_temp

Takeoff power is almost never maximum engine power.

Maximum power affects engine life as it brings significant wear to the engine. IIRC, if max power is used on takeoff, the crew must log an entry in the logbook to notify maintenance.
Turbo-fans produce a lot of power. If you require max power to takeoff, you better double-check your numbers, or you're operating with a pretty narrow margin.

The reality is the reverse: airlines love to do low power takeoffs, and they avoid a high power takeoff as much as practical. Occasionally, a condition such as high ambient temperature (resulting in high pressure altitude), heavy load, obstacle on departure path may demand a max power takeoff. Possible wind shear may also prompt the crew to select a higher takeoff power.

Typically, how much margin is available above takeoff power for max engine power?

Also if take off power isn't max engine power, when is max engine power used? Any circumstances you can think of? Is go around thrust at max engine power?

@curious_cat: max power is used in unusual situations, such as in turbulence, wind shear, go around, engine failure etc. Usually, around 90~95% N1 is sufficient on takeoff. In very good conditions, it may even be slightly below 90% (e.g. 87 or 88%).

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Is there a rule of thumb for aircraft design?
I'm wondering how to best scratch build an rc aircraft and what rough proportions the aircraft should be in.
I'm aware of the fineness ratio that determines the width to length ratio of a cross section of a wing should be around 1:3 or 1:4, but I can't seem to find similar rules for:

The distance between the wing and tailplane
The length of the wings

Am I just better off just making a scale model of an established aircraft instead of using these rules?

The question is likely too broad. I'd say find a good book or two on R/C airplane design. Stay away from scale to begin with; the proportions don't scale down to R/C that well.

You could improve this question by providing more focus. Do you want your aircraft to do acrobatics or be a basic trainer, go supersonic or incredibly slow? What kind of materials do you want to build with?

@Krish the rule of thumb is to use your brain.  Start with the application and work back to your design.  Speed is a very critical starting point.  Straight wings are best for slower flight.  A longer fuselage makes it more stable.  Read up on gliders, and aircraft in general.

This is another question that would be better on https://area51.stackexchange.com/proposals/123448/drones-and-model-aircraft

No, there isn't any single rule of thumb for airframe shape.  Just look at the huge variety of airframes that have been built and flown over the years.
One way to scratch-build is to start with a cardboard glider that's roughly the shape you want.  Tape the wings and tail to the fuselage in different places, tape on some noseweight, give it a toss, deflect the elevator, give it another toss, vary the dihedral, sweep, decalage.


text:
In track while scan mode of radar operation what are the methods to predict next position of target?
In a track while scan system (TWS) the algorithm states that the processor predicts the next position of the target and compares it with the actual position but what are the actual methods of prediction?

Speed of target, heading of target, climb/descent rate of target, targets announced intentions or ATC directed routing.

@CrossRoads Please don't answer in the comments

I didn't have a firm source, so I commented instead of answering.

Standard approach for radar tracking is as follows:

Prediction of next position using one Interacting Multiple Model per aircraft. The basic model is made from two Kalman Filters, one of which predicts constant velocity (in 3D), the other predicts a constant-rate turn (also in 3D). The model selects the prediction from the filter that performed better during the last few updates.
Data from the scan arrives. Positions of the blips are compared to the predicted positions and the Joint Probabilistic Data Association technique is used to associate each blip with one of the tracked aircraft. If there are unassigned blips, a new model is set up to track the newly discovered aircraft.
Each aircraft's model is updated with the associated blip's position. This includes updating each Kalman Filter as well as selecting which of the filters should be used for the next prediction (the one that predicted the current blip more accurately).

Thanks for the answer

The obvious choice would be to implement a higher order Kalman filter. This would give an estimate the state of each target (position, velocity, acceleration). The challenging part would be to tune it correctly for the dynamics of the type target to be tracked and the noise characteristics in the radar measurements.
With an estimate of the initial state of the target (after the last plot), the position of the target after a brief scanning period can be easily estimated; simply integrate the acceleration and velocity vector over time and you know the change of position.
Not only would the state of the Kalman filter help in predicting (a priori) the new position of the target, it would also be able to tell you something about the accuracy of that prediction. That is of great help when associating the next plot from the radar to the right track, in case multiple targets are being tracked.

This Thesis from 1979, titled "Comparison of an $\alpha$ - $\beta$ and Kalman filter in Track While Scan Radars" by Dimitrios Emmanuel Mayiatis of the Naval Postgraduate School in Montery California shows an example of the application of a Kalman filter in TWS radars.

Thank you its helpful


text:
What causes 'wing rock' and how does it work?
Currently studying for a course on fighter aircraft. I came across the phenomenon of 'wing rock', which occurs at very high angles of attack, but I couldn't find any good sources that explain how this phenomenon works in detail. Could anyone give me an explanation of the mechanics of this phenomenon?

NASA sponsored a research paper on this. https://ntrs.nasa.gov/search.jsp?R=19850037432  There are quite a few other papers on this subject. Your educational institution should be able to get you access to them.

Thank you for the resource!


text:
What are the labels for this aircraft's JSON?
Can someone please help me identify the labels associated with the below JSON?
The data comes from FlightRadar24
c5cded9":[
          "06A0F8",
          51.3056,
          6.4601,
          283,
          43000,
          459,
          "3245",
          "F-EDDK1",
          "A359",
          "A7-ALD",
          1486231556,
          "DOH",
          "LHR",
          "QR1",
          0,
          64,
          "QTR1",
          0
]

I get that 51.3056 & 6.4601 are the latitude and longitude. I also get that 43000 is the altitude and 1486231556 is a timestamp, but I do not know what the others should be...
For example, LHR I guess is London Heathrow, but is what is the official term?
I'd like official terms to match the JSON.
I want to do some data visualizations with the aircraft data.

It might help if you edit your question to indicate where the JSON comes from an it's purpose.

FR24 explicitly does not have a published API, and they probably won't take too kindly to someone using their internal API (which they should secure.... ).

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Does the European Aviation Safety Agency (EASA) provide real-time data feeds and is there a delay?
According to this answer:

You can't get real-time data from the FAA without an operational need, and organizations which do receive real-time data cannot legally re-distribute this data publicly, except to other organizations approved by the FAA. An operational need pretty much means you have to be a flight dispatcher for an airline or commercial operator, not just have an interest in tracking flights.

Great, now apparently, the data feed is delayed by at least 5 minutes... according to this answer.

Does the EASA provide data such as that provided by the American
FAA?
If so, is there also a delay on data?

If so, what is the delay?

Thanks!

EASA does not provide any live (or non live) flight data feed. Neither Eurocontrol. At least AFAIK. Don't take for granted that FAA's responsibilities/capabilities/services have a 1:1 match to EASA's.

Please note that the linked answer is outdated. Last April the FAA dropped the 5 minute delay from its feed.


text:
What is the name of the previous Air Traffic Management System (ATMS) of Hong Kong International Airport?
Hi I really need help for the question.
The current ATMS for Hong Kong International Airport is the AutoTrac III, but does anyone know what is Hong Kong's Previous ATMS?

Could it be the AutoTrac II? And where have you checked already? Have you tried contacting them?

I have checked through their Civil Aviation Department and little information about their previous ATMS. I have yet contacted them.

It was AutoTrac I, also from Raytheon.

Oh, thank you! If possible, do you have the specs about the AutoTrac I? (such as the Primary surveillance radar & Secondary surveillance radar ranges and their respective rotation rate, etc.) If unable to provide, then it is alright. Thank you again, as now at least I have a lead for my research.


text:
Clarification on flight hours as compensation
I've seen the phrase "flight hours as compensation" before, and would like some clarification on it. What I've read seems to generally concern operating an aircraft on a PPL for a commercial purpose, basically meaning if you fly an aircraft and don't cover "your share" of the aircraft expenses, then recording your flight time may be considered compensation by the FAA. What I'm wondering is, does it stop being considered compensation after you get a commercial license? If I have a CPL and fly for hire, paying no expenses of the flight, are my flight hours considered compensation in addition to my wage? Do I have a legal right to those hours? Is a company allowed to, as a condition of employment, require that I don't log hours while flying their aircraft? If a company suddenly and without reason sticks me behind a desk instead of having me piloting an aircraft,  would the loss of flight hours be considered a pay cut?

Welcome to aviation.SE! A lot of this seems to be more about employment law than FAA regulations. If you don't get a good answer here you might try law.SE as well. The [tour] may also be helpful to see how this site works.

There are a few different questions in here, some are FAA regulated and some are a matter of the terms of your employment

If I have a CPL and fly for hire, paying no expenses of the flight,
  are my flight hours considered compensation in addition to my wage?

Maybe, its somewhat up to your employer, but more importantly its not really what the FAA cares about. You have a CPL and are presumably flying for a legal carrier/operation. In the eyes of the FAA they don't much care how you are paid beyond that. Practically the legislation is more to ensure that people who are getting paid are properly licensed and working for a proper operator.

Do I have a legal right to those hours?

As Juan notes if you were PIC (or SIC) properly certified in the aircraft then the time is yours.

Is a company allowed to, as a condition of employment, require that I
  don't log hours while flying their aircraft?

That seems like it would be encouraging you to not follow a FAR which is not a great idea.

If a company suddenly and without reason sticks me behind a desk
  instead of having me piloting an aircraft, would the loss of flight
  hours be considered a pay cut?

This depends two things, your existing contract with your employer, and if that contract changes when your job changes. Often times with a role change your contract, or the terms of the original undersigned contract can be changed. If you were a pilot with a Minimum Monthly Guarantee in your contract you may be entitled to keeping your pay-rate. However if the new job comes with a contract change or shifts where you are under your current contract you may not be entitled to anything.

If you are a PPL and don't cover your share of the flight it is illegal because you don't have a CPL, regardless of whether you logged the time or not. Unless you have a reason to go to the destination where the other people in the aircraft are going, it's not going pass muster. The regulations do not state that the hours amount to compensation either. From FAR 61.113:

(c) A private pilot may not pay less than the pro rata share of the
  operating expenses of a flight with passengers, provided the expenses
  involve only fuel, oil, airport expenditures, or rental fees.

Notice that the reg doesn't say that you can charge for your time as expenses or be reimbursed for it, pro-rata or otherwise.
To the other part of the question, no, a company cannot prohibit you from logging your hours. That would be a violation of FAR 61.51. But if you're transferred to a desk job, that's an issue related to your employment contract, and I doubt any court in the US would hear a case saying you have a right to be compensated merely for the flight hours you would fly if you kept your flying job. You might get the difference in compensation if the flying paid more than sitting at a desk, but not for the flight hours per se.
Also, being transferred from one position to another ALWAYS happens for a reason. Just because you don't know what it is, or don't agree with the reason, doesn't mean there isn't one.

Thanks for replying, but now I'm even more confused. How does the FAA think you've been compensated if you dont cover your share of the flight? Say you're going up just to fly for fun, and your buddy tags along and pays for the flight as a thank you, but doesnt give you anything. How have you been compensated?

@W2555 Because the regulation says that, as a PPL, you can't pay less than the pro rata share of the operating expenses. If your buddy pays 100% of the operating expenses, you've paid less than that. I'd also note that the FAA at one point had a legal interpretation that directly stated that "Generally, accrual of flight time is compensation." That doesn't mean the same interpretation would apply to a labor dispute with your employer, which would be a pretty different situation.

The regulation is not about compensation. You can't even take passengers for free and pay all the costs if you were not going to the destination in the first place, except in specific circumstances such as, for example. taking a sick pax from point A to point B with a non-profit org.

"You can't even take passengers for free and pay all the costs if you were not going to the destination in the first place..."  Do you have a specific reference for this?  I don't recall where the CFRs delineate who has to come up with the idea to go flying.

See https://www.faa.gov/about/office_org/headquarters_offices/agc/practice_areas/regulations/interpretations/data/interps/2009/mangiamele%20-%20(2009)%20legal%20interpretation.pdf.


text:
What is a "KALP114A" ATC regulation?
My flight (in Spain) was delayed for 6h and after I submitted the claim the airline worker answered me that it was delayed due to KALP114A regulations imposed by ATC, but I didn't find any info, that such regulation even exists.

the regulation KALP114A, which caused delay, was introduced directly on the flight by Air Traffic Controllers

The flight was on the 14th of April, 2019, from Spain to Germany.

Within Europe, whenever there is need to reduce the number of flights through a certain airspace, the Network Manager (Eurocontrol) puts in a so called "regulation". This results in flights planned through the regulated airspace being delayed or re-routed.
Regulations are given an ID; those starting with KALP are from the Karlsruhe Upper Area Control (EDUU), southern sectors (Alps) above Flight Level 315.
Since your flight was over three weeks ago, I can't check the exact "regulation Id" in the public database, but it is likely that it was related to staffing issues at Karlsruhe upper area control centre.
An example of a current regulation starting with "KALP" is below:

Karlsruhe UAC has severe staffing problems and is causing many traffic delays this year.

A delay of 6 hours due to a regulation sounds extreme to me. I don't know what the origin and destination of the flight was, but typically a re-routing avoids the regulated airspace with only a short delay.


text:
What is this airplane that sits in front of Barringer High School in Newark, NJ?

This airplane sits in front of Barringer High School in Newark,Nj. No one there can identify it. Anyone have any idea of the make and model? Thanks

Just out of curiosity, even if no one there can identify the make/mode, does anybody there at least have some idea why it's there?

@ZachLipton conversation piece and advertisement. The high school probably has an aviation program.

My daughter is a teacher at that school. Shes been told they had an aviation program years ago.

Some googling shows that the words on the back are "AEROSPACE ACADEMY", and that a Carmen Ruiz was a 1982 graduate and another Carmen Ruiz was the principal in 2008, possibly the same person.

It's a Fourney Aircoupe  that's seen better days. Much better days...

Notice the aircraft went through several manufacturers and names during its troubled life (it wasn't exactly a commercial success). Most commonly known as ERCO Ercoupe.

The strangest iteration being the last one, the Mooney Cadet  https://en.wikipedia.org/wiki/Mooney_M10_Cadet

IIRC the Aircoupe has no rudder pedals, the rudder is interlinked with the yoke. Must make crosswinds landings interesting.


text:
How to know which data came from Mode S and which came from ADS-B (FIS-B)?
I'm dealing with recorded ADS-B data as a part of my thesis (programming-oriented).
I have a table of ADS-B communication of an aircraft (image below) - I know, that some of these recorded data in the table come from Mode S and some from ADS-B system itself. I need to know which of these data (GPS coordinates, heading, TAS, Mach and meteo data) come from the Mode S and which come from ADS-B (or FIS-B).
I'm unable to find any source, that would distinguish between data sources of these data.

All the recorded transmissions you have, seem to come from the same aircraft. They come all from the onboard (Mode-S) transponder.
All transmission with Downlink Format (DF) 17 are ADS-B. Those with DF18 are TIS-B (or ADS-R), you don't have any of these (they are rare in Europe, and more common in the US)
Mode-S uses the following DF's:

DF4 - altitude reply (short)
DF5 - identiy reply (short)
DF11 - all call reply / Mode S squitter
DF20 - Comm. B / altitude reply (long)
DF21 - Comm. B / identity reply (long)

Thanks. Yes, this is one aircraft only.
So none of these data come from direct SSR Mode S addressed communication but from ADS-B only? I just want to be sure, I am not even sure, if its possible to record direct radar-transponder communication with ads-b receiver.

Only those with DF=17 are from ADS-B. The DF20 and DF21 in your table are Mode-S replies.  It's perfectly possible to record direct transponder>radar communication with an ADS-B receiver. I've done so for a living (and still do sometimes).

Okey, thank you very much. I understand it now. TIS-B/FIS-B ground systems are not available in Europe (afaik, if you know about some, tell me please :-) ). One more thing (sorry to bother you) - what is the possible source of meteorological data (as in table above) in ads-b communication? FIS-B only? Or is there some alternative like adding it later?

Meteorological data is not available in the current version ADS-B (ED-102A / DO-260B) but is planned for the next version.

Okey, thank you very much :-)

ADS-B has two defined datalinks, 1090ES and UAT978.
UAT978 is, so far, only available in the US.
FIS-B is weather radar and similar data, and is only available on UAT978.
1090ES datalink is an enhancement to Mode S that adds DF17 messages with position, velocity and other ADS-B data.
TIS-B is a ground-based service that transmits ADS-B-like messages on behalf of radar targets that do not send their own. In the case of 1090ES, it uses DF18.
ADS-R is another ground based service that relays ADS-B messages on one datalink to another. Since the only country with two datalinks today is the US, that's the only place you'll see ADS-R messages. For 1090ES, it also uses DF18. It can be distinguished from TIS-B by the address type field.

Thank you. What is the DF code for FIS-B messages, please?

@Václav There is no FIS-B on 1090 MHz, so no DF for FIS-B

Okey, thank you very much :-)


text:
FOD ingestion & engine damage - how does the crew know it happened?
A 737 I was supposed to fly on yesterday was grounded after, per the captain, it ingested a pebble on the taxiway causing damage to a fan blade. My question is: how did they know this happened? (Lucky for us they had a spare plane coming in right at the next gate & were able to get a full planeload of us out with only a couple hour delay.)

The pilot and co-pilot actually have a much better field of view than one may expect from the cock pit. Now while one of them may have seen the pebble get ingested by one of the engines this is where the facts end. But the damaged fan blade is simply an educated but more than likely correct assumption. The only way to confirm the damage though is to cut power to the engine(s) and conduct a visual inspection as well as an internal borescope inspection of the engine itself. From personal experience while working on turbofan engines for the F/A18 Hornet and Super Hornets. It's rare that you would only have damage occur to only the blades of only a single module.

Most likely either the captain or the first officer spotted the damage during a preflight walk around of the A/C and reported it to maintenance.  The flight crew deemed the damage to be a flight safety risk and that the aircraft was no longer airworthy until it could be repaired.  While rare, engine damage due to FOD ingestion occasionally happens.  That’s why we do preflight inspections to physically inspect the airframe, engines and other systems for any signs of damage prior to flying.


text:
Why would an airport have a "Z" approach unless there's also a "Y" of the same type?
Napa Airport (KAPC) has an ILS Z 1 approach, but no ILS Y 1. See here. Why isn't this just the ILS 1? The naming rule described in the IPH, referenced here, doesn't explain why this would happen.

A reason could be Y was cancelled and Z was not renamed, this is usual. But the most probable reason is the scope for numbering is not the airport but the city. See Why is there a "-D" circling-only approach at an airport that does not have corresponding -A, -B, and -C approaches?.

mins, thanks for the link. I don't think there's any other "Napa" in California though.

Yes I realized that just a few seconds ago, but I actually found a Y procedure.

Ah, cool! How do you find historical plates? The faa search only allows current & next options. ETA: never mind. You can manually edit the URL query string to get older dates.

@mins Sounds like an answer?

@StephenS: I think at the time we considered the question was not relevant anymore since ILS Y actually existed at a time (cannot find it anymore, the link is dead).


text:
Confusion about center-of-lift vs center-of-gravity
As usually depicted, in a small aircraft (maybe larger commercial ones too), the lift due to the main wing (excluding the elevator) is depicted as on average aft of the center of gravity, with the negative lift of the elevator compensating for the resulting torque in straight and level flight. This is longitudinally stable because a slight pitch up movement will increase the AOA on the wing and, up to stalling, the resulting increase in lift acting behind the CG will cause a pitch down torque, and vice versa.
My confusion is about stalling. When the main wing stalls its lift decreases, resulting in pitch up torque. So why does the nose drop? You can, I believe, trim a small plane so that it will execute a series of pitch up, stall, pitch down, recover cycles with no input from the pilot. What is the explanation of the pitch down torque on a stalling aircraft? Is it due to the elevator losing (negative) lift as the airspeed drops?

Intuitively:  When pitched up a lot, both the wing and the tailplane are making more drag than lift.  Then the tailplane's lever arm about the CG is what "weathervanes" the airplane back to level.

Does this answer your question? Why do airplanes usually pitch nose-down in a stall?

As usual, Peter answers clearly and concisely.  https://aviation.stackexchange.com/a/96155/31425

What is the explanation of the pitch down torque on a stalling aircraft?

Sometimes this is a simple matter of wing design.  In setting our aircraft for most efficient flight, through a combination of trim and ballast, we can set the aircraft center of gravity at, or near, the center of lift, so that little trim is needed to maintain level flight.  In other words, the center of lift for the full wing is at and through the center of gravity.
Most wings are designed with slight washout, meaning that the outer panel of the wing has been twisted to reduce the angle of attack of the wing in that outer panel region.  If we examine lift across the entire wing with the airplane in trim, the center of lift for the wing is through the center of gravity for the plane.  And, considering flight speed and wing loading, the center of lift may be very slightly ahead of the center of gravity. Why?  One additional factor at play is the pitching moment of the wing.  In neutral flight, most wings have a negative pitching moment, meaning the wing has a very slight tendency to pitch downward even when the aircraft is in trim.
As the wing stalls, the stall progression usually begins at the wing root and progresses outward across the inner panel of the wing.  The wing tip, however, is unstalled because washout gives that section of the wing a lower angle of attack.  Consequently, absent lift from the functional inner panel, the center of lift for the outer panel is slightly behind the center of gravity, thereby causing a slight nose-down moment during the stall. This can be assisted by the very slight downward pitching moment of this unstalled portion of the wing. Hence, the nose pitches down.

You can, I believe, trim a small plane so that it will execute a series of pitch up, stall, pitch down, recover cycles with no input from the pilot.

As we can well imagine, if the airplane is in a near-trim condition, and a stall is incurred, the nose will pitch forward and the aircraft will gain airspeed.  As this occurs, the unstalled condition of the wing is restored, and with the center of lift restored, the aircraft will gently pitch nose-up in recovery.  If the pilot does not capture this recovery with a slight down elevator trim input, the aircraft will continue on an upward path, losing airspeed, and once again stall.  This process may continue ad-infinitum until corrective action is taken.
Some aircraft are designed so that the wing is completely neutral; the center of lift for the wing is always through the center of gravity for the plane.  The nose down tendency of the wing is incurred then, only by the pitching moment of the wing.  Consequently, the plane must be actively flown to maintain its flight attitude.  What planes fly like this?  Think pylon racers.  Or Mike Patey's Turbulence.  (Oh, boy!)

I don't think washout has much to do with it. My understanding is that washout has two benefits: stalls are gradual and ailerons retain some control effect. I think what others have said here or linked to about the elevator weathervaning as the the plane starts to drop is the explanation. Also, the center of lift for the main wing is not at the longitudinal CG, it's behind it. The elevator's negative lift counteracts that resulting torque.

"Consequently, absent lift from the functional inner panel, the center of lift for the outer panel is slightly behind the center of gravity" you have a swept-back wing in mind, correct? In that case your explanation doesn't work for airplane with a straight wing, like many GA airplanes. You have also forgot to mention one of the most important aspects making the airplane pitching nose down i.e. the change of the AoA of the tail when the wing stalls

@FosterBoondoggle  My apologies, but I do not know of anyone who flies that way. Zero trim is the rule of the day.  That means flying a balanced airplane having no negative elevator lift.  The view I presented was just one aspect not intended to be all encompassing and universal.  That was clear in my initial paragraph.

@sophit  I am not going to get into a comment argument with you on this issue.  Evidently, you have studied Gracian and know him well.  The swept wing tends to stall at the tip first.  And as I mentioned to Foster, the airplane is in trim. The answer I presented was simply one aspect, apparently from a different than usual point of view.  There are many others, such as yourself, who could add perspective with a different view.

@ThomasPerry: we can exchange also without arguing . I don't know Gracian, I'll have a look at it. Your answer in correct I just wanted to add an important ingredient which is the change in the AoA of the tailplane when the root of the wing stalls


text:
Is there an FAA definition of what "normal flight operation" means?
Some documents talk about normal and abnormal operation. Is there a definition by FAA what normal operation is?

Your question is about normal and abnormal procedures, or about weather conditions, or about something else. Please may be you may develop the question

They way it is used, it seems to distinguish between normal and abnormal operation (so the way the airplane is flown) based on whether or not failure scenarios (e.g. one engine out) apply. Usually in design you only need to consider one failure scenario at a time, hence for the assessment you would assume "normal" operation.  Question is if the term is defined or if the use of that term is ambigious.

Can you give us more details about the documents, and include a quote from one of them? That might help to give you a useful answer.

VTC as needing more details, i.e. examples of the "some documents" referenced at the beginning of the question.

I don’t think there is a specific FAA definition of “normal operations” as what is normal will depend on what you’re doing, what you are flying, the condition at the time.  I think for all intents and purposes that normal operations are what the Pilot Operating Handbook states for a given aircraft as outlined in the Normal Procedures section. Outside of that I would have to consider normal operations is anything following the FAR/AIM for a given flight or flight maneuver.  For example, following the preferred method of entering a traffic pattern at a non-towered airport would be considered normal operations.


text:
Is the true altitude always lower than the indicated altitude as long as a correct local altimeter (QNH) is set on the altimeter?
Given the fact that the altimeter setting is corrected for the temperature of the airport, on the condition that a correct local altimeter setting (QNH) has been made to the altimeter, is the true altitude always lower than the indicated altitude as the altitude increases above the airport elevation regardless of the temperature of the airport, since the temperature generally drops as the altitude goes up?
For example, even when the temperature in the airport is, say, above 30 degree Celsius, do we still fly lower than the indicated altitude of, say, 5000ft, just like when we do when the temperature is below 15 degree Celsius, standard ISA temperature?

No, the true altitude can also be higher than the indicated altitude, if the temperature is higher than expected from the International Standard Atmosphere (ISA). This case is usually not as important as the opposite case because flying at higher true altitude does not create a risk due to terrain clearance.

In a standard atmosphere, the indicated altitude
reflects the true altitude above the mean sea level
(MSL) and therefore provides a reliable indication of
terrain clearance.
Whenever, the temperature deviates significantly
from the standard temperature, the indicated altitude
correspondingly deviates from the true altitude, as
follows:

Extreme high temperature: the true altitude is higher than the indicated
altitude,
Extreme low temperature: the true altitude is lower than the indicated
altitude, thus creating a lower than anticipated
terrain separation and a potential obstacle clearance hazard.

(Airbus - Approach-and-Landing Briefing Note - 3.1 - Altimeter Setting - Use of Radio Altimeter)

I think the collision of Il-76 and 747 in India was caused by Ilyushin flying higher than indicated, so it's not always harmless.


text:
"Cancel altitude restriction." Under ICAO rules, does it cancel all altitude restrictions on a SID or STAR chart?
Let's say there are altitude restrictions at 5000ft, 11000ft, 15000ft, 18000ft on a SID chart. While you were following the SID (under ICAO rules), the Departure tells you "Climb 12000ft, cancel altitude restriction." Does this instruction cancel all altitude restrictions on the chart or only restrictions below 12000ft?


text:
Why does the FMC in B737 limit the climb speed to 230 knots on the VNAV mode until the leading edge devices are fully retracted?
In the VNAN climb on B737, the FMC changes the target speed from V2+20kt at liftoff, to 230kt for acceleration at the preset accleration height, then to 250kt (below 10,000ft) as the leading edge devices are fully retracted along with the trailing edge flaps.
My question is: Why is the climb speed limited to 230kt on the VNAV mode until the leading edge devices are fully retracted, when there are only operating speed limits to trailing edge flaps as below?

For your information, I've found a discussion on this topic on another aviation website but no one seems to have a definite answer to this.
https://www.pprune.org/tech-log/570676-737ng-led-s-speed-limitations-ops.html
Does anybody have a good answer to this?

That's a really good question. I would like to see an answer :)

One of the reasons may be to leave a safety margin. For example, if you are with Flaps 10, you are not gonna fly at 210K IAS, but something less (or the maneuverability speed for Flaps 10). Same thought process for slats deployed.

Does it always target 230KIAS regardless of weight? In your question it’s not quite clear whether 230KIAS is upper limit of VNAV initial climb speed range or whether it’s a fix target. Also, FLAPS 1 limit speed implies slat limit speed, but is labelled only FLAPS in accordance with flaps handle (which operates the slats, too).

It's a fixed target regardless of the gross weight

The non normal checklist QRH will answer your question.  If the LE flap transit light remains illuminated I.e the leading edge flaps and slats haven’t retracted or disagree with the flap handle position, then the QRH directs you to limit the speed to  230 kits until you have rectified the issue.  VNAV is honouring that restriction.
Hope that answers your question.

The logical follow-up is, with flaps extended to 1 or 5, the barber pole limit is 250 knots. So as the leading edge devices retract, you're still restricted to 250, rather than 230. Given that VNAV will climb (clean) at speeds within a few knots of VMO (given a high cost index), why does it buffer the 250 knot limit by a full 20 knots?

@RalphJ Presumably because the Le FLAPS TRANSIT light can also indicate a leading edge device asymmetry or skew according to the QRH. This would result in different aerodynamics compared to the normal flaps 1 or 5 settings.

@Bianfable  I'd be okay with that answer if the operating limitation were "230 kts until LE FLAPS TRANSIT extinguished," but it isn't. We can fly the airplane at 250 knots; why such a different speed with VNAV?

@RalphJ As far as I understand the QRH, you also shouldn't fly the airplane at more than 230 kt until the light extinguishes because you cannot know if there is an asymmetry. The 250 kt limit is for flap 1, 2 or 5 fully extended with light out. At least this would be my interpretation, maybe 737Pilot can shed some more light on this...

Taking into account in advance the possibilities of a future failure doe not comply with the rules of the art. That’s not flying. When a fault occurs you follow the respective procedure, no pilot is requested in advance to follow a hypothetical failure checklist, QRH or not!

One of the FMC major objectif is to reduce fuel consumption, beyond this speed the lift to drag is too much expensive
Definitely it is neither a safety reason nor a structural protective reason, otherwise the barber pole won’t be at 250 knots.
None is obliged to follow the FMS, and the autopilot is not mandatorily on VNAV, it could be on manual selected speed, and in this case the selected speed could be as high as 250 knots.

Because at flaps 1, the leading edges are deployed until the flaps are up therefore 250K speed restriction

True, but that would still allow 250KIAS. OP states the FMC flies at 230KIAS for Flaps 1.

In B737max The greater the speed the greater the pitch instability if not counteracted at low speed. If flaps are retracted at high speed it would be worse, but happily FMC does limit speed to 230 knots with flaps at 1 ( like 737 NG) for fuel reduction considerations, not structural.


text:
Can we always trust the PAPI lights?
I have a question about the PAPI system. One of the first things student pilots learn during their ground school is the PAPI. You get two whites and two reds on a visual approach, you're on the 3 degree glide path. If you get three reds and one white, you're a little low. If you get four reds, then you may consider going around since you're way too low.
My question is: Can we always trust the PAPI lights? Is there no chance the PAPI lights might be wrong, so for example, when you get three whites and one red on the 5 mile final, but you are actually below the 3 degree glide path?

Related: What is the average deviation from the PAPI glide slope at the threshold?

Yes, you can trust the PAPI lights. As usual in aviation, safety is priority #1, this also applies to airport lighting, which is checked and monitored continuously.
PAPI lights are calibrated regularily to ensure their indications are correct. As with all technical equipment, there is a non-zero risk PAPI lights may fail, however, given how simple they are (literally just a light bulb, a colour filter and a lens - no moving parts) a failure is very unlikely.
You should note that not all PAPI lights are calibrated for a 3° glidepath. While 3° is most common, there are runways where the normal approach angle is different and the PAPI lights will be calibrated to that. So make sure to check the airport charts before using the PAPI system, or you may risk coming in steeper or shallower than you are used to.
Also note that, as pointed out by @wbeard52, approaching with the PAPI showing two whites and two reds is not a guarantee of obstacle clearance if you are far from the runway - it is only a guarentee that you are following the nominal glideslope of the approach procedure with which the PAPI is aligned.

For a student pilot, PAPI gives an easy reference, but one really should learn to judge glidepath without PAPI, VASI or any technical aid... I know this sounds like oldskool bs, but you prolly are not going to always fly to airfields with tech aids...

If you capture the PAPI too far out, it may not keep you safe.  See my answer below.

For some examples of steeper glideslopes than 3-deg : Do any airports have a steeper standard approach than London City?

@Jpe61 that's not oldskool bs, judging an approach by sight alone is very important and very accurate. Humans are pretty good at discerning small angular differences.  More than once I've been on final and it looked right, but the papi was showing all red/all white, and when reported it was discovered the box had been knocked out of alignment somehow.

No, you should not ALWAYS trust any one thing, you cross-check all the available information.  As @nexus_2006 says, accidents happen, and especially at smaller airports, may not get reported & repaired immediately.  Say for instance the person mowing the grass around the runways happens to hit the box and doesn't bother to report it.

@jamesqf  That's really the best answer - if OP is looking for a heuristic, that's 100% it.  Only trust what you absolutely need to and double check anything you're able to.

@nexus_2006 re " ...  and when reported it was discovered the box had been knocked out of alignment somehow. ..." -> That's such a strong real worls NO!!! answer that it really should be an answer !

Before I experienced it myself, I agreed with your opinion, that a PAPI is very unlikely to fail. Then I came out of the clouds on an IFR approach at about 500ft and saw the PAPI indicating: white/red/white/red. I don't know what was wrong with it, but a NOTAM was published afterwards that the PAPI is now out of service until repaired.

@TobiBS I would expect that a failed PAPI will usually (always?) show something nonsensical like red/white/red/white so that it is obvious that there is a failure.  I don't know that there are any design rules that require this, but it seems a sensible fail-safe behaviour.  It would be interesting to know if a PAPI can fail showing something normal (ie: indicating [W/W/R/R] but you're way off the GS).

@J... You do understand that a PAPI has no moving parts? Each of the four lights are always showing both white and red, you only see a difference depending on the viewing angle

@expeditedescent No moving parts, but loaded with electronics.  TobiBS saw white/red/white/red.  That should be physically impossible unless something mechanically fell apart in the unit.  I'm saying there could be command and control electronics that can perhaps detect a mirror misalignment, tilt, etc, and may change the colour of the lights projected on the hi/lo paths to produce a nonsensical pattern to the viewer to accentuate the fact that the unit is not to be trusted.  Just theorizing how it might be done, like I said, I don't know.

@J... Perhaps. I'm no expert either. But I would imagine it would be hard to detect dew/condensation on the lens for example

@expeditedescent It looks like there are some rules (AC 150/5345-28G, section 3.9.5 Excessive Light-Unit Tilt) stipulates a number of tilt-sense requirements and failsafe modes.

@J... Well it could theoretically do that, if e.g. all lamps are mounted on a bar and then the whole bar gets bent, e.g. by a truck backing up during construction. But I agree that if only one lamp/optic has an issue, normally the error should be clear.

As with all things in aviation, there is a service volume or limit to the area PAPI and other visual approach lights ensure obstacle clearance.  It is important to know what those limits are.  I have heard of multiple accidents where the pilots were on the PAPI but still hit terrain because they intercepted the PAPI lights too far out without much thought about the terrain around them.
Please reference AIM 2-1-2

Precision Approach Path Indicator (PAPI). The precision approach path indicator (PAPI) uses light units similar to the VASI but are installed in a single row of either two or four light units. These lights are visible from about 5 miles during the day and up to 20 miles at night. The visual glide path of the PAPI typically provides safe obstruction clearance within plus or minus 10 degrees of the extended runway centerline and to 3.4 NM from the runway threshold. Descent, using the PAPI, should not be initiated until the aircraft is visually aligned with the runway. The row of light units is normally installed on the left side of the runway and the glide path indications are as depicted. Lateral course guidance is provided by the runway or runway lights. In certain circumstances, the safe obstruction clearance area may be reduced by narrowing the beam width or shortening the usable distance due to local limitations, or the PAPI may be offset from the extended runway centerline. This will be noted in the Chart Supplement U.S. and/or applicable NOTAMs.

Visual Approach Slope Indicator (VASI).  The VASI is a system of lights so arranged to provide visual descent guidance information during the approach to a runway. These lights are visible from 3-5 miles during the day and up to 20 miles or more at night. The visual glide path of the VASI provides safe obstruction clearance within plus or minus 10 degrees of the extended runway centerline and to 4 NM from the runway threshold. Descent, using the VASI, should not be initiated until the aircraft is visually aligned with the runway. Lateral course guidance is provided by the runway or runway lights. In certain circumstances, the safe obstruction clearance area may be reduced by narrowing the beam width or shortening the usable distance due to local limitations, or the VASI may be offset from the extended runway centerline. This will be noted in the Chart Supplement U.S. and/or applicable notices to airmen (NOTAM).

This is an interesting point, but, it doesn't mean per se that you can't trust the PAPI outside 3.4NM - the indication should still be correct. It just means that obstacle clearance might not be guaranteed beyond that distance. OP is asking specifically if the indication may be wrong: "for example, when you get three whites and one red on the 5 mile final, but you are actually below the 3 degree glide path?" (still upvoted btw)

BTW as far as I can tell from ICAO Annex 14, the ICAO standard is a protection surface of 7500 m (4 NM) for code 1 and 2 runways, and 15000 m (8 NM) for code 3 and 4 runways

Even if obstacle clearance isn't guaranteed, you have to be visual anyway to see the PAPIs. This obviously implies that you can also see obstacles between you and the runway (except maybe "invisible" ones like power lines, but they are not nearly high enough to be a threat when you are 4NM out).

@Bianfable  I would tend to agree with you.  If you can see the PAPI's then by definition there is nothing between your eyesight and the runway.   Unfortunately, there is the underside of the airplane that could be subjected to terrain even though you can see the PAPI's.  During the day, you will most likely see that terrain and fly higher or around the mountain.  At night, you will only notice the lights surrounding the terrain leading to the runway start to disappear as you get close to the runway.  It is those dark spots at night (in a city environment) that concern me.

still hit terrain because they intercepted the PAPI lights too far out Source?  If you can see the PAPI, how can terrain later appear between you and the lights?  Unless it's pitch black... and you're flying VFR?

The source is in the answer.  Just because you can see the lights, that means there is no terrain between your eyesight and the runway.  There is still 5 FT in a Cessna 172 that can hit terrain below you.  It has happened before.

@wbeard52 I guess I mean that if you're VFR you should be able to see the terrain between you and the lights regardless, so it's not really about the lights...

@wbeard52: It might not be the terrain you hit, but the power lines on the 40 ft poles running along the crest of the hill :-)

When you're wondering about failure, usually one of the first things to consider is failure modes. Bulbs burn out, power can fail, etcetera. But the symptoms you mention do not match those failure modes. An earthquake could, but in that case the runway itself may have bigger issues.

If you fly in cooler climate, frost on the PAPI lenses has been known to cause false signals. See Transport Canada Aerodrome Safety Circular (ASC) No. 2002-014, available here. Mitigation strategies make it fairly unlikely that you will encounter this.
In Canada, if ATC is operating, they will switch them on to warm them up in advance of an arrival. In places where pilot-controlled-lighting is used (called ARCAL in Canada), you might see the PAPIs left on continuously for the same reason.
I'm with wbeard52, these things have a maximum range, even though you might see them from way further out. Make sure you're close enough before you start using them.

One thing to keep in mind when flying GA small aircraft is that often the papi is not ment for us but for bigger craft which touchdown point is often 1000ft after the threshold. Being on the papi to intercept the  glide path far from the runway and then aiming for the threshold will alway gives you higher slope than expected. When learning to land you'll probably focus on the threshold and thus you'll most of the time have 4 reds on final even if you are following the right slope.
Otherwise if you're aiming for the right landing point, you can trust the papi as it is checked quite often for safety reasons.


text:
Are there statistics showing the relationship between safety and the age of aircraft?
Some people seem to believe that some airplanes are less safe to fly just because they are older than others. As a pilot myself who has learned that the safety of aircraft is nothing to do with their age as long as they are properly maintained in accordance with the regulations regarding airworthiness, I take the idea to be wrong and try to talk those people out of their idea whenever I come across them. Some people are persuaded but some are not.
I believe there are nothing better than brute facts in changing one's belief and here is my question: Are there statistics that support the idea that old aircraft are no less safe than new aircraft?

Regarding your belief that that's "nothing better than brute facts in changing one's belief": have a look at changingminds.org. There is a whole lot better than brute facts, and a substantial body of research suggests that facts can be counter-productive. There is, for example, a well-known bias in which we more easily disregard information that doesn't fit our current opinion/worldview, whereas we do accept information that confirms what we already believe.

Regarding the content of the question (especially the clarification given in your comment on user71659's answer): I don't know of a database that readily provides the information you're looking for, but using the production lists of popular (commercial) airliners on Airfleets.net you might be able to make such a statistic yourself. You can sort the lists to find all s/n that have been "written off", then compile an Excel-sheet of first flight and crash date, compute the difference and see whether there is a trend.

I could not find statistics, so I parsed the data available on https://aviation-safety.net/database. This site does have a statistics page, but it does not have an answer to your question.
I'm not a statistician so I'm sure there are much better ways to crunch and graph this data, but the raw data I found was:

The data includes 5075 crashes from the years 1919 - 2019.
The mean aircraft age is 15.58 years. This age is the age of the particular aircraft involved in the crash, not the "age" of the aircraft's type.

I did not normalize the data in any way, so take it with a grain of salt and except some skews and outliers (for example, a 75 years old DC-3 crashed earlier this year - https://aviation-safety.net/database/record.php?id=20190121-0). On the other hand, crashes in the early years will naturally skew the data, as every aircraft that crashed was new at the time of the crash.

The answer is no. Statistics show that new types have lower accident rates than older types.
Airbus has grouped aircraft into 4 categories: early jets, autopilot jets, glass cockpits, and FBW jets. They state

The lowest sustained fatal accident rate of first generation jets was around 3.0 accidents per million flights, whilst for the second generation it was around 0.7, meaning a reduction of fatal accidents of almost 80% between generations. In comparison, third generation jets now achieve about 0.2 accidents per million flights, a reduction of around a further 70%.
Finally, fourth generation jets have the lowest accident rate of all, at a stable average rate of about 0.1 fatal accidents per million flights, which
is a further 50% reduction compared to the third generation.

They provide charts (page 17) which show that the accident rate of FBW planes is half that of third-gen glass cockpit planes over the last 10 years.
New aircraft have features like auto-TCAS, auto depressurization descent, and landing distance monitoring, that aren't available on older models. These enhance safety.
Certainly certification and crashworthiness standards have improved over time. For example, 16 G crashworthy seats were introduced in 1988. Improved access to exits and fire resistant materials were other requirements phased in by the FAA.
And finally, the FAA now has the position that you cannot maintain an aircraft safely forever, with regulations called the Limits of Validity. As an aircraft ages, the structure incurs fatigue damage. At one point, the damage will be so prevalent, that cracks will merge and you'll have an Aloha 737 accident.
Concerns that such damage will be missed or occur in areas that cannot be inspected have led to the LOV, which is an upper flight cycle/flight hour limit at which the aircraft must be scrapped. Notably, this was something that Soviet/CIS certified aircraft always had.

Thank you for your answer but it seems a little off the point. When I compared older aircraft to new aircraft, what I meant was a comparison between older aircraft versus newer aircraft in age, not one between aircraft in different generations with different technology, for example between 20-year-old B737NG and and brand-new B737NG, not between B767 and A350.

@lemonincider "not one between aircraft in different generations with different technology, for example between 20-year-old B737NG and brand-new B737NG" A 20-year-old B737NG and a brand-new B737NG also have different technologies.

seems Airbus has removed that document as I'm unable to see/download it :(

Just from the factory new may not be the best. Many electronic devices (and there are lots of them in a modern airliner) have the short "burn in" period when they fail more often, here and more realistic plots here. Then there is a long service period when they are reliable, and ultimately the reliability degrades again as the device gets old and should be replaced.
I would probably pick an airliner that have already flown few hundreds of hours.


text:
Are there two types of runway holding position sign?
I came across this section on runway holding position marking while reading Jeppesen Airway Manual, which got me very confused.

My question is: Is Pattern B describing another type of runway holding position sign other than the one described in Pattern A? Or is it just describing the ILS critical area boundary marking for CAT II & III approaches? I'm asking this question because I've never heard in my whole aviation career that there are "two" runway holding position markings, nor seen one.

You are correct. It is marking the ILS critical area boundary. I think they apply to Cat I as well.(Our airpoart has them and it has a Cat I ILS)  https://www.boldmethod.com/learn-to-fly/regulations/holding-short-of-ils-critical-areas/

The Jeppesen description is confusing (to me) but have a look at the AIM 2-3-5 and specifically Figure 2-3-16:

It looks like the pattern A image you posted shows runway holding position markings only; pattern B shows runway holding position markings and ILS holding position markings.

I’ve never seen the critical area hold bars referred to as a type of runway hold bars, but they serve the same general purpose when the critical area needs to be protected, so I can understand the point of describing them together.

The "pattern B" markings designate the boundary of the ILS critical area, from which aircraft (and other things) are excluded during ILS operations. An aircraft exiting the runway knows it is safely outside the ILS critical area by passing that boundary marking.